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Controlling the Si/C ratio in SiC matrix based on the modified polymethysilane for C/C-SiC composites with enhanced mechanical properties

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Journal of Advanced Ceramics 2024年第2期13卷 220-236页

作者： Mingdong Liao Xiebo Hu Chenghao Zhong Ping Xu Xiaodong Wang Ze Zhang Peng Zhou Mingyu Zhang Zhean Su Qizhong Huang National Key laboratory of science and technology on High-Strength Structural Materials Central South UniversityChangsha 410083China

Fabricating SiC matrix with controllable Si/C ratio for C/C-SiC composites via precursor infiltration and pyrolysis is difficult to realize due to the absence of suitable ***,SiC precursors with Si-rich(Si/C=1.23),nearstoichiometric(Si/C=1.01),and C-rich(Si/C=0.88)pyrolyzed ceramics at 1200℃ were successfully synthesized by the novel modification of *** structure and ceramization of synthesized SiC precursors were studied,and C/C-SiC composites with similar Si/C ratio in SiC matrix were also *** results revealed that the defects and Young’s modulus of SiC matrix and the thermal residual stress on pyrolytic carbon coated carbon fiber were determined by the Si/C *** a result,the Si/C ratio exerted significant effects on the crack deflection behavior and the mechanical properties of the *** composites with near-stoichiometric SiC matrix showed excellent mechanical properties because of the effective crack deflection and the moderate Young’s modulus of their SiC *** flexural strength,flexural modulus,and compressive strength were 423±27 MPa,33.41±4.52 GPa,and 393±8 MPa,***,after a heat treatment at 1600℃,the role of carbon fiber toughening was improved and accompanied by a decrease in mechanical properties for all composites,which was attributed to the increased defects in SiC matrix and the damaged interfaces by the thermal residual stress.

关键词： SiC precursor Si/C ratio polymethysilane C/C–SiC composites mechanical properties

Electronic and Thermoelectric Properties in SnS-Nanoribbon-Based Heterojunctions

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Chinese Physics Letters 2024年第9期41卷 63-68页

作者： Kai-Bo Zhang Shi-Hua Tan Xiao-Fang Peng Meng-Qiu Long Hunan Province Key laboratory of Materials Surface or Interface science and technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric *** extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 *** Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are *** results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁-ASNSNR(N𝑁is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L𝐿represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of𝐿-SNSGNR are larger than those of𝐿-*** calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in𝐿L-SNS-GNR at room temperature,and over 4 in𝐿L-SNS-Au and 2.6 in𝐿L-SNS-GNR at 500 K.

关键词： material. sulfide ribbon

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Copper oxide-modified highly reversible Zn powder anode for aqueous Zn metal batteries

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Rare Metals 2024年第10期43卷 5005-5016页

作者： Guan-Qun Liu Biao Fu Zhe-Xuan Liu Lan-Yan Li Shu-Quan Liang Guo-Zhao Fang School of Materials science and Engineering Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan ProvinceCentral South University School of science Hunan University of Technology and Business National Energy Metal Resources and New Materials Key laboratory Central South University

With the advantages of mature preparation technology,structural adjustability and suitability for large-scale application,Zn powder anode is considered to be an ideal electrode for realizing low-cost,high-energy-density aqueous Zn metal ***,the high specific surface of Zn powders leads to severe side reactions such as hydrogen evolution and corrosion,thus limiting their widespread use Here,this work develops a novel CuO@Zn powder anode with a synergy effect of surface wrapping and *** powders are uniformly wrapped by small CuO particles due to the strong adsorption between Zn and *** wrapped CuO particles build a good conductive framework to inhibit the structural collapse of the Zn powder caused by corrosion and non-uniform ***,CuO can also be used as a seed to guide the uniform deposition of Zn ions through its strong binding energy with *** a result,the Cu O@Zn anode can maintain a long cyclic life of 900 h at current density of 1 mA·cm-2and capacity of 1 mAh·cm-2,as well as contribute to an excellent capacity retention of 92%after 800cycles for CuO@Zn||NH4V4O10full *** at high current density of 5 A·g-1,the full cell exhibits a specific capacity of more than 200 mAh·g-1after 800 cycles,with a good capacity retention of 89%.This work provides a new idea for developing high-performance Zn powder-based anodes.

关键词： Aqueous Zn metal batteries Copper oxide Surface wrapping Zn anode Zn powder

Physics-informed deep Koopman operator for Lagrangian dynamic systems

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science China(Information sciences) 2024年第9期67卷 146-163页

作者： Xuefeng WANG Yang CAO Shaofeng CHEN Yu KANG department of Automation University of Science and Technology of China State Key laboratory of Fire science University of Science and Technology of China Institute of Advanced technology University of Science and Technology of China

Accurate mechanical system models are crucial for safe and stable control. Unlike linear systems,Lagrangian systems are highly nonlinear and difficult to optimize because of their unknown system *** research thus used deep neural networks to generate linear models of original systems by mapping nonlinear dynamic systems into a linear space with a Koopman observable function encoder. The controller then relies on the Koopman linear model. However, without physical information constraints, ensuring control consistency between the original nonlinear system and the Koopman system is tough, as the learning process of the Koopman observation function is unsupervised. This paper thus proposes a two-stage learning algorithm that uses structural subnetworks to build a physics-informed network topology to simultaneously learn the Koopman observable functions and the system energy representation. In the Koopman matrix learning session, a quadratic-constrained optimization problem is solved to ensure that the Koopman representation satisfies the energy difference matching hard constraint. The proposed energy-preserving deep Lagrangian Koopman(EPDLK) framework effectively represents the dynamics of the Lagrangian system while ensuring control consistency. The effectiveness of EPDLK is compared with those of various Koopman observable function construction methods in multistep prediction and trajectory tracking tasks. EPDLK achieves better control consistency by guaranteeing energy difference matching, which facilitates the application of the control law generated on the Koopman system directly to the original nonlinear Lagrangian system.

关键词： Koopman operator Lagrangian physics-informed nonlinear model predictive control (MPC)

Enhancing I0/I-Conversion Efficiency by Starch Confinement in Zinc-Iodine Battery

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Energy & Environmental Materials 2024年第1期7卷 118-124页

作者： Danyang Zhao Qiancheng Zhu Qiancheng Zhou Wenming Zhang Ying Yu Shuo Chen Zhifeng Ren Institute of Nanoscience and Nanotechnology College of Physical Science and Technology Central China Normal University National & Local Joint Engineering laboratory of New Energy Photoelectric Devices College of Physics Science and Technology Hebei University department of Physics and Tc SUH University of Houston

The redox couple of I0/I-in aqueous rechargeable iodine-zinc（I2-Zn）batteries is a promising energy storage resource since it is safe and costeffective,and provides steady output ***,the cycle life and efficiency of these batteries remain unsatisfactory due to the uncontrolled shuttling of polyiodide（I3-and I5-） and side reactions on the Zn anode.

关键词： aqueous battery conversion efficiency iodine–zinc battery starch confinement

Flexible sensors with zero Poisson's ratio

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National science Review 2024年第5期11卷 153-169页

作者： Xin Huang Tianzhao Bu Qingyang Zheng Shaoyu Liu Yangyang Li Han Fang Yuqi Qiu Bin Xie Zhouping Yin Hao Wu department of Mechanical Engineering Flexible Electronics Research Center State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and Technology department of Electronic science and technology School of Integrated CircuitsHuazhong University of Science and Technology

Flexible sensors have been developed for the perception of various stimuli. However, complex deformation,usually resulting from forces or strains from multi-axes, can be challenging to measure due to the lack of independent perception of multiaxial stimuli. Herein, flexible sensors based on the metamaterial membrane with zero Poisson's ratio(ZPR) are proposed to achieve independent detection of biaxial stimuli. By deliberately designing the geometric dimensions and arrangement parameters of elements, the Poisson's ratio of an elastomer membrane can be modulated from negative to positive, and the ZPR membrane can maintain a constant transverse dimension under longitudinal stimuli. Due to the accurate monitoring of grasping force by ZPR sensors that are insensitive to curvatures of contact surfaces, rigid robotic manipulators can be guided to safely grasp deformable objects. Meanwhile, the ZPR sensor can also precisely distinguish different states of manipulators. When ZPR sensors are attached to a thermal-actuation soft robot, they can accurately detect the moving distance and direction. This work presents a new strategy for independent biaxial stimuli perception through the design of mechanical metamaterials, and may inspire the future development of advanced flexible sensors for healthcare, human–machine interfaces and robotic tactile sensing.

关键词： zero Poisson's ratio metamaterials independent perception of multiaxial stimuli flexible sensor

Direct Synthesis of Layer-Tunable and Transfer-Free Graphene on Device-Compatible Substrates Using Ion Implantation Toward Versatile Applications

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Energy & Environmental Materials 2024年第5期7卷 412-422页

作者： Bingkun Wang Jun Jiang Kevin Baldwin Huijuan Wu Li Zheng Mingming Gong Xuehai Ju Gang Wang Caichao Ye Yongqiang Wang department of Microelectronic science and Engineering School of Physical Science and Technology Ningbo University Key laboratory of Soft Chemistry and Functional Materials of MOE School of Chemistry and Chemical Engineering Nanjing University of Science and Technology Center for Integrated Nanotechnologies Los Alamos National Laboratory National Key laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Academy for Advanced Interdisciplinary Studies & department of Materials science and Engineering Southern University of Science and Technology Guangdong Provincial Key laboratory of Computational science and Material Design Southern University of Science and Technology Materials science and technology Division Los Alamos National Laboratory

Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device *** of the art in the field is currently a two-step process:a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition (CVD)followed by delicate layer transfer onto device-relevant ***,we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area,high quality,and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer process.

关键词： device applications dual-metal smart Janus substrate growth mechanism Ion implantation layer-tunable and transfer-free graphene

In Situ-Constructed LixMoS2 with Highly Exposed Interface Boosting High-Loading and Long-Life Cathode for All-Solid-State Li-S Batteries

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Energy & Environmental Materials 2024年第4期7卷 163-174页

作者： Hao Li Rui Wang Jiangping Song Dan Liu Hongyang Gao Yimin Chao Haolin Tang A State Key laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology department of Chemistry Chemical Engineering and Life Science Wuhan University of Technology Foshan Xianhu laboratory of the Advanced Energy science and technology Guangdong laboratory School of Chemistry University of East Anglia

As the persistent concerns regarding sluggish reaction kinetics and insufficient conductivities of sulfur cathodes in all-solid-state Li-S batteries(ASSLSBs),numerous carbon additives and solid-state electrolytes (SSEs) have been incorporated into the cathode to facilitate ion/electron pathways around ***,this has resulted in a reduced capacity and decomposition of SSEs.

关键词： all-solid-state lithium–sulfur batteries conversion/intercalation high-loading and long-life low carbon content mixed ionic/electronic conductivities

Topological magnetoelectric response in ferromagnetic axion insulators

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National science Review 2024年第2期11卷 8-14页

作者： Yuhao Wan Jiayu Li Qihang Liu department of Physics and Shenzhen Institute for Quantum science and Engineering(SIQSE) Southern University of Science and Technology Shenzhen Key laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Guangdong Provincial Key laboratory for Computational science and Material Design Southern University of Science and Technology

The topological magnetoelectric effect （TME） is a hallmark response of the topological field theory,which provides a paradigm shift in the study of emergent topological ***,its direct observation is yet to be realized due to the demanding magnetic configuration required to gap all surface ***,we theoretically propose that axion insulators with a simple ferromagnetic configuration,such as the MnBi2Te4/（Bi2Te3）nfamily,provide an ideal playground to realize the *** the designed triangular prism geometry,all the surface states are magnetically *** a vertical electric field,the surface Hall currents give rise to a nearly half-quantized orbital moment,accompanied by a gapless chiral hinge mode circulating in ***,the orbital magnetization from the two topological origins can be easily distinguished by reversing the electric *** work paves the way for direct observation of the TME in realistic axion-insulator materials.

关键词： topological magnetoelectric effect axion insulator magnetic topological materials